I have added a choice to the list of a field of a hosted feature layer. When I edit it in the web map, it displays the feature template with the recently added choice. When I edit in the app (WAB) using the editor widget, the new choice is not there in the feature template.
I've tried:
re-adding the layer fresh to the map
deleting and re-adding the editor widget into the app
We want to make sure the changes you made are written into the layer's feature templates JSON.
In your web map, go to Manage the editing templates, make some changes (make sure the template for the choice you've added is there, and make some other change even if it's bogus, you can always change it back and save again) and save changes.
Then from the layer's options, click Save Layer
Finally save your web map and refresh your web application.
Let me know if your changes now appear in the Edit widget.